1. Field of the Invention
The present invention relates to multi-stage power supplies that can be applied to displays or lighting systems, and more particularly, to a multi-stage power supply that can integrally control DC/DC converters connected in multiple stages.
2. Description of the Related Art
Recently, the production of LED monitors and LED TVs has been gradually increasing. The levels of LED driving voltages of these LED monitors or LED TVs are determined according to the number of LEDs that are connected in series with each other. In particular, as screen size increases, a higher DC driving voltage is required.
In the case that an insufficient amount of direct current is supplied using one DC/DC converter, research and development has been conducted on power supplies in which a plurality of unit DC/DC converters are connected in multiple stages.
An LED TV requires a DC driving voltage of 40V, 80V or 80V or higher. When an external adaptor is used, a direct current of 14V is generally applied, and DC driving voltage may be boosted up to 40V using a one-stage boost converter.
When a DC driving voltage of 80V or higher is required, it is difficult to supply a DC driving voltage of 40V or higher with a one-stage boost-up converter. When a voltage of 40V or higher is supplied using a one-stage boost-up converter, efficiency is very low, and heat being generated from components is serious. For this reason, two or more boost-up converters are generally used to thereby supply a voltage of 80V or higher.
This existing multi-stage power supply includes a plurality of boost-up converters and a plurality of PWM control sections respectively controlling the plurality of boost-up converters.
However, the existing multi-stage power supply needs to have the plurality of PWM control sections, thereby increasing manufacturing costs and power consumption to operate the plurality of PWM control sections.